Flasher



July 7,. 1 953 n. -s."P'ERRY 644.5899

Y FLASHER Filed July 29. 1939*- 2 Sheets-'Sheet 1 @L my 64 F/GZ .Elu 12R. s. #ERRY July 7, 1953 FLSHER 2 sneetsneet z Fuga July 29, 1949v #M TmTDM N N. R s o @fm /m PM Patented July 7, 1953 FIJASHER Robert S.Perry', Westfeld,..N. .J..',.. assignor; by

mesne assignments, to Perry'lilasherSyndicate;.v

Westfield; N. J.

Application July 29, 1949, Serial No`."107,497 l 1.6 Claims. l.

Thisinvention relates to an automatic switch or"asher for periodicallymakingand breaking an electric circuit.V It. isfoften desirable tointermittently operate orllash an incandescent lamp at short regularinterval's'in order'to draw attention to'the'light. This is particularlydesirable in certain advertisingfdisplays andy in warninglights. It iscommonto provide automobiles with indicator lights to-warn` the driversof other automobiles of inten'- tion to turn or stop. These lights areYpreferably blinked or intermittently operated to attract greaterattention.

Inl' the form.. shown, the present invention is applied to a asher forblinking the turn indicator lights of an automobile. The flasher unitcomprises a stack of metallic'plates, a portion of one of which forms amovingswitch arm that is arrangedto be controlled by a hot wire. Theswitch, which is spring biased to closed position, is connected in shuntof the not wire; and the hot wire'is connected. in series with the lightthat istobe flashed. When the wire is cooly it holds the switch open,and the current which then passes isinsuiiicient to light the lampA butsucient..to. heat the wire. As the wire heats it lengthens, permittingthe switch to close and shunt. out. the wire. The. current .i that thenpasses is sufhcient to light the lamp, and the lamp remains'lighted.until the hot wire has cooled sufciently'toopen the switch and therebyrestorethe circuit to its initial condition. This cycle.is;thenrepeatedv again and again, so that they light. continues to blink;Thegiiasher shown may becombined with a relay for; operating a pilotlight toindicatefthe operation'. of the lights controlled by theflasher. l

, A feature-sof the. present invention is that rapid closing and openingof the'. switch is secured solely by the interrelationship of. only twoopposing moments,` the.: switch arms always being biased `towards closedposition. rAnother feature ofthe invention is .that due to the'specicconstruction and arrangementmost .ofthe factors controlling therduration of the. on and oli periodsmay be very closely controlled,final. adjustment being made during assembly solelyby thetensioning ofthe hot wire. The specific'confstruction permits a relativelylargeamount of tolerancein this adjustment without adversely affectingoperation of` the flasher.

An object of the present invention is .topfovide'an improved flasherthat is durable, .sufficiently shockproof, easily assembled andadjusted,v4 and.` that will. retain its adjustment indeiintely.

Another object of.; the invention is toprovide anew and improvedmethodof .periodically interrupting: an: electric circuit.

Another object is to provide an improved flasher and relay combined in asingle, unitary structuregthat lends: itself. to quick and easyassembly:

Another object is to generally improve flashers of the.. type described;

Further objects, and objects relating-to details and. economesrofmanufacture, assembly and usa-.zwillmore denitely'appear from thedetailed description to follow.

My; invention is'clearly denedin .the appended claims.r Where parts are,yfor clarity and `convenience., referred. to on the basis. of theiroriented. position shown in the accompanying drawing, no limitation asto positioning of the entire structure isxto be implied.' since it willbe understood that the entire structure may be in- Vertedfory that it`may be used in any inclined position. Also in both the description andthe claims, parts at times may be identied by specificA names forclarity and convenience, but such nomenclature is to be understoodashaving thefbroadestmeaning consistent with the context andw-ith theconcept of my inventionas distinguished from the pertinent prior art.The bestiorm' in which I have contemplated applying my invention isillustrated in the accompanying `drawing forming `part of thisspecification, in which:

Figure. 1 is :a schematic diagram showing the flasher. ofthe-presentinvention applied tothe control of asingle lamp. K

Figure 2. is awiringxdiagram of the combined flasher and relay asapplied toya Iturn signalling system of an automobile;

Figure 3 is an explodedisometric View of the combined ii-asher :andrelay.

Figure 4.- is a top plan View of the plateof the v flasher that providesthe switch arm and biasing is pivotally mounted at a pivot point I5.This spring engages against an end of the switch arm II, pressinglengthwise of the arm, the portion of the arm between the pivot I2 andthe spring being rigid, A substantially rictionless knifeedge connectionI6 (see also Fig. 6) between the arm and spring retains the spring inengagement with the switch arm, the arm and spring forming essentially atoggle. However, the knifeedge connection I6 always remains on the sameside of the neutral axis through the pivot points I2 and I5, theabutment I1 serving to prevent the knife-edge connection I6 fromcrossing this axis. Thus, the spring I4 continuously biases the switcharm Il laterally in the same direction, i. e. toward closed position.The spring I4 is sufciently long so that there is no substantial changein length of the Spring as the switch arm II oscillates and the pressureof the spring on Y the switch arm is substantially constant.

A stationary contact I9 of the flasher is positioned to be engaged by acooperating movable contact 26 mounted on the switch arm II adjacent theknife-edge connection I6, the flasher being in the on position when thecontacts are L Wire 22 may be formed of the nickel-chromemanganese-ironalloy resistance wire `commonly known as Nichrome The length of the wire22 is such that at atmospheric temperatures the wire 22 is under tensionand exerts a pull on the end portion 2I of the switch arm II. Thisdeflects the portion 2I of the switch arm somewhat and oscillates theswitch arm against the abutment I1. The contacts I9 and 20 are nowsepa-rated. As the temperature of the wire 22 increases, the wirelengthens somewhat due to expansion, lessening the moment on the switcharm I I and permitting the spring I4 to oscillate the switch arm in theopposite direction so as to close the contacts I9 and 20.

An electrical lead 25 is connected with the switch arm Il, and thecontact I9 is connected directly to a lamp 26 by a conductor 21. Theabutment end of the hot wire 22 is connected with the conductor 21 by aconductor 29. The arrangement is Such that when the iiasher is in normalor starting condition, the wire 22 is cold (i. e. at atmospherictemperature) and the contacts I9 and 20 are separated, the switch arm IIresting against the abutment I1, and the end portion 2I of the switcharm being deiiected upward slightly due to pull of the wire 22.

Upon establishing an electrical circuit to the lead 25, as by manuallyclosing switchv I3, the wire 22, which is of relatively high resistanceand in series with lamp 26, will be heated by the passage' of electriccurrent, although the current will be insunicient to light the lamp '26.As the temperature of the wire 22 increases, it lengthens somewhat andthus decreases the force or moment tending to hold the switch arm I Iagainst the abutment I1. When the effect of the hot wire pull on switcharm II drops below the eiect of the biasing spring I4, the lspring I4oscillates the switch arm with a snap action. This closes the contactsI9 and 20 and establishes a direct connection between the lead 25 andthe lamp 25 to light the lamp, the flasher then being in the positionindicated in Fig. l.

Inasmuch as the direct circuit through the contacts I9 and 20 is of verylow resistance as compared with the circuit through wire 22,substantially all of the current passing through lamp 26 will passthrough the direct circuit and the current passing through hot wire 22will drop to substantially Zero. The wire 22 is of such small diameterthat it cools quickly. As it cools, it shortens and increases the forceor moment exerted by it on the switch arm II until it overpowers themoment caused by spring I4. At this point the contacts I9 and 20 areseparated with a snap action and break the direct circuit to the lamp26, whereupon the cycle will commence again. By varying the specificdesign of this flasher within the general construction and arrangementabove set forth, the time interval of both the on and 01T periods of thelamp 26 may be accurately controlled or varied, as well as the timeinterval required for the entire cycle.

Increasing the air gap between the contacts when in off position orincreasing the pressure of the spring I4, decreases the number offlashes per minute, the other factors remaining the same, whileincreasing wire tension increases the number of flashes per minute. Anincrease of voltage or any other factor that increases the rate at whichthe wire 22 heats and lengthens tends to increase the number of ashesper minute. For the ordinary signalling lamp a rate of about to flashesper minute is desirable, with the on period approximating the offperiod.

A feature of the construction shown diagrammatically in Fig. 1 is thatas the wire 22 becomes heated and lengthens, the end portion 2l of thearm straightens and the wire 22 swings toward the pivot I2, thusdecreasing the moment which the wire imposes on the switch arm II. Whenthis moment falls below the opposite acting moment on the switch armimposed by the spring I4 with the contacts fully opened, the switch armoscillates to closed position. As the switch arm commences to move awayfrom the axis of the pivots I2 and I5, the moment caused by spring I4increases rapidly, the pressure being substantially constant and thelever arm rapidly increasing. At the same time, the counteracting momentimposed by the hot Wire is relatively constanty the end portion 2I ofthe switch arm being deflected slightly. Thus, the contacts close with afast snap action.

`After the contacts I9 and 20 have closed, the wire 22 will commence tocool and shorten thus exerting a constantly increasing force on theresilient end portion 2I of the switch arm II. This force deflects theportion 2| of the arm upwardly, thereby storing energy in springyportion 2 I and creating a constantly increasing counteractinlgr momenttending to open the contacts. When this moment exceeds the moment of thespring I4, the contacts will open. As the contacts start to open, thelever arm at which spring I4 acts on the switch arm I I diminishesrapidly, thereby rapidly .diminishing the bias whichtends to close thecontacts. Thus, the contacts snap open quickly, under the influence ofthe energy stored in springy portion 2I of the switch arm.

While the counteracting moments are substantially equal in each instanceat the instant the movement of the switch arm II commences.- in

leaclrinstance 'the degree ci 'unbalancevery rapidlyincreasesasthecontact 2-fmoves, thereby producing-faiveryrapidmake-or break ofthe con` tacts I 9- and Zliwith'out theinterplay of any force other thanthe forceof thehot wire 22 and the force of the biasing spring I4. y l IThe il'asher previously described may beconstructed/ of a= stack;orfpile of steel plates that have been cadmium plated to preventrusting. The plates have peripheral edge portions provided withholes-for reception of rivets` tof secure the assembly, theedgeportionsof the plates collectively forming a-frame or housing `for the op'-eratingAV portions of the flasher; In describing the'plates and theassembly made therefrom', corresponding parts will bedesignated'by thesame reference characters-usedein Fig. 1.

"Referencew-ll now be had to Figs: 4 and 5, which-show a two-part steelplate composed of parts vand .3i-which lie ina commonplane and meetend-to-end at 33. Metal is stamped out from part 3l? as shown-to haveacentrally located projectingv spring Iwhich is the biasing spring I4"of-Fig.A 1'.r4 By means of overlapping kerfs 3l, 39land 31, 39 themetallic connection between spring I4 and the outer portion of part 30`is so reduced and arranged as to form (in effect) the-pivoted connectionI5 (see also Fig. 1).

Metal is similarly stamped out from plate part 3I to form a portion ofswitch arm I I. By means of overlapping kerfs 32, 34 and 32, 34themetallic connection between the arm I I and the outer por- AtionV ofpart 3I is reduced and arranged to form (in eiect) the pivotedconnection I2 (see also Fig. l).

The end portion 2| of the switch arm I I, for receiving the hot wire 22,may be tapered from the pivot I2 so as to bend uniformly throughout itslength under the pull of wire 22. A rigid strip 35 is secured to theremainder of the switch arm I I by-rivet 36 and provides a rigid armfrom the pivot I2 to the knife-edge connection I6. The contact 2i! isformed of a strip of silver inlaid on one side of the strip 35 adjacentthe knife-edge connection I8 (see also Fig, 6), the inlaid strip alsoforming one side of a slot receiving the free end of the spring I4 toform the knife-'edge connection. The portion 2| of the switch arm I I is4laterally oiiset somewhat as indicated in'Fig. 4 to provide clearancefor the hot wires'when both the iiasher'and relay are combined in asingle structure, as in Fig. 3.

Referring now to Fig. 3, the entire stack of plates and parts'formingthe iiasher and relay arev shown in exploded relation. plates areprovided with registering marginal holes used to facilitate assemblyv ofthe flasher and to receive rivets or other fasteners for lsecuring theassembled plates.

A plus or line terminal plate 4I, which is positioned adjacent to thebottom of the stack of plates, is provided with a terminal 42 forreceiving the wire 25 of theFig. l and is also provided with a bridgeportion forming the abutment I'I that prevents the knife-edge connectionitfrom passing below the axis of the pivots I2 and I5. The underside ofthe line terminal plate 4I is covered by a cover plate 44 to inclosethe'bottom 'of the nasher unit. The inside ofthe cover plate may beinsulated from plate 4I by a coating of lacquer.

- The next plateof the series comprises the two- Apart-plate 3Q, 3l ofFig. 4, this plateincluding the switch arm II- and spring I4.' Abovethis plate ris provided aspacer plate-45fwhich may be coated All ofthese 6 with-lacquer tov insulate 'it from the plate next above rThisplate: determines-the air' gapzzor spacing betweenthe contactsnl 9 .and'ZU-Whenthe switch arm II is againstftheabutment II'."` Above the spacerplate-.a5, afplate 46 is providedwhich hasfa vbridgeporti'on forming thecontact I9. `A

smallosilver contactbuttonl-m'ay be provided -on Y the bridge portion ofthe plate if desired.

The next succeeding: plate 41 is formedin two U-shapedfparts asindicatedv inFigr. dior-:convenience of assemblyof the'iiasher.vThis-:plate is provided: at one end witha knurled portioniformze ingthe/abutmentA 24 for receiving an end-ofthe hot vwire `i2 extending toythe'switch armfII. For convenience-of attachment ofthe wire 22 to theportionZ I of theswitch'arm, it is desirableitouuse a-single wire havingitsvmid portion looped'.l about theportion 2! ofthe switch armand thetwo `ends attachedfto the. abutment 254,- thetwo-branches of'v the`wires functioning together as asingle lengthV of hot wire. l

Thenext succeeding four plates, including: the spacer plates and'EI andwhich are similar to the spacer plate B5,- therelay terminal plate 50,and the two-part switch arm and spring plate-52, 54 needbe insertedonlywhen it is desired to have aA relayincorporatedin the iiasher unit'. Thenature andiunction of these four plates will-be explained hereinafter.If thesefourvplatesare omitted; the load terminal plate- 43,-. which isidentical to plate 4I but in invertedl position, may loe-mounteddirectly on plate 4l,A theterminall'48 of the plate [itreceivingthewirel leading tol'- the lamp or lamps 2S to bey controll'edlA second cover plate 44, which ils-lacquered on'the inside, covers thetop of plate 43.

With the relay plates omitted the current pass'- ing into the lineterminal plate lil-is conducted into plate portion 3I= and switch arm II, from whence the current passes upwardlythrougli the wire=22 and tothe load terminal plate 153.' When the contacts i9 and 2c are closed byupward movement or the switch arm- II, the current passes directly fromthe switch arm II to the plate dt, theplate 4l and intotheplate '435morder to light the lamp.

' When the relay is incorporated in the flasher, it :may be connectedinto a circuit for indica-ting to'la person driving an automobile thatthe signal lamps are in operation. In a form shownof this invention, theflasher unit is designed to flash a lamp at both the front and rear ofthe car to indicate a vright or left turn. The relay is pro'- videcl tocontrol a monitor circuit lighting a pilot light 551(Fig. 2) on theinstrument panel of the automobile. I

The physical structure of the` relay switch-'is generally similar tothat of `the flasher switch hereinbefore described. The switch arm `andspring plate portions 52 and 540i therelayv are identical` respectivelywith plate portions SI and lljiof the flasher but in inverted position.Below these plates, the spacerv plate 5i', which is insu?- latedfbylacquer on its top surface, serves to space the switch arm 53 from therelay terminal plate 5i), which is providedwith a bridge portion form.-ing acontact 5S for the switch'armof the relay. A spacer plate 49, whichis insulated by lacquer on its top surface, separates the plate 5c fromthe abutment plate 4l.

A hot wire 5'I serves to operate theY relay," this wire being similarlyarranged to the wire 22' but of much lower electrical resistance. In theflasher of the present invention as applied to 6 volt automobileelectrical system; the-hot wire 22 may have an electrical resistance ofabout 2 ohms while the hot wire 51 may have a resistance of about onehalf ohm or less. The hot wire 51 is in series with hot wire 22, thelatter wire being cyclically shunted by the closing of contacts I9, 20.When the signal lamps are lighted, the lampcurrent passes through wire51, but is shunted around wire 22.

. A front signal lamp is in parallel with a rear signal lamp and,therefore, when both are operating, the current through hot wire 51 istwice as great as when one of these lamps has burned out. The action ofthe relay is such that when both the front and rear signal lamps of theautomobile are operating, the wire 51 is heated sufiiciently to enablethe relay switch arm 53 to engage the contact 56 of the relay terminalplate 50 to complete the circuit to the pilot light 55 (Fig. 2) while,if one or both of the lamps at the front and rear of the car are notoperating, there will be insufficient current passing through the Wire51 to cause it to heat and expand sufficiently to complete the circuitto the light 55.

Since the wire 51 is sufiiciently heavy it will not, once it has beenheated, cool enough during the time that the direct circuit to the lampsis interrupted by the flasher to cause the relay circuit to the pilotlight to be interrupted. However, when the direct circuit to the signallamps is interrupted, the relatively large resistance of wire 22 isintroduced into the circuit and this extinguishes the pilot lamp 55 thesame as the signal lamps 26. Thus, the pilot lamp hashes when bothsignal lamps are flashing.

The construction of the flasher unit is particu* larly adapted for easeof assembly. The flasher is assembled on studs, not shown, the platesbeing individually stacked from bottom to top on studs passed throughholes 59, 59 and 60, 6U in the bottom cover and the corresponding holesin the rest of the plates. By this arrangement, the switch arm platepart 3l may be inserted first and the spring plate part inserted laterso as .to engage the end of spring I4 with the switch `arm l I to formthe knife-edge connection I6.

The right end part of the abutment plate 41 is slipped in after theremainder of the plates have been assembled, this part of the plate 41having a pair of open holes or slots to permit later insertion onto thestuds.

After assembly of the flasher, rivets 6I (Fig. 2) may be insertedthrough the marginal holes to `hold the entire stack of plates inassembled relation, the rivets being temporarily omitted from lthe pairof holes at the right end of the asher. The rivets are insulatedthroughout their length to prevent electrical contact with the plates.

Small wedges, not shown, may be introduced :between the abutment end ofabutment plate 41 and the next adjacent plates 46 and 49 to space theseplates slightly until the wires 22 and 51 have been properly tensioned.After tensioning the wires to the predetermined tension for the flashercharacteristics desired, the Wedges may be removed permitting the platesto come together and rigidly clamp the wires. The remaining rivets arethen added to aid in holding the entire assembly.

The flasher of the present invention has a rigid case formed of thesteel plates, which is not easily distorted. The moving parts are heldto .a minimum and there are no fragile parts thus assuring dependabilityof operation and making lthe device resistant to physical shock andotherwise very durable.

The pivots I2 and I5 formed by the overlapping kerfs are easily formedand are durable. Also, the pivot l2 may deflect or raise somewhat underpull of the wire 22, forming in effect a somewhat resilient pivotandvpermitting greater tolerance in adjusting the tension of the wire.

The flasher may be incorporated in the circuit indicated in Fig. 2. Inthis circuit, the automobile battery 62 or other source of power isconnected with the line terminal 42 of the flasher. A selector switch 64of a well known type, which is customarily mounted on the steeringcolumn. is connected with the load terminal 48. The selector switch 64may be operated to illuminate either the right-hand or the lefthandpairs of lamps 26 to indicate either a right turn or a left turn, itbeing understood that one lamp of each pair is on the front of the carwhile the other lamp of the same pair is on the rear of the car. Therelay terminal plate 50 is connected with the pilot light 55 to indicateoperation of both lights 26 of the selected pair.

The flasher and relay of the present invention does not include anyelectro-magnetic device, and hence is equally suitable for use witheither direct or alternating current.

I claim:

l. The method of obtaining rapid acceleration for the opening andclosing of the contacts of a ilasher for interrupting an electricalcircuit at frequent regular intervals, the flasher having a contact armmounted for pivotal movement and the arm being continuously biasedtowards closed position by a momentwhich varies between a maximum atclosed position of the contacts and a minimum at fully open position,said method comprising: applying a counteracting moment to the arm andvarying the counteracting moment to alternate it between values greaterthan the maximum and less than the minimum of the biasing moment, andstoring the energy of the counteracting moment without any relativemovement of the contacts until such time as the ccunteracting momentovercomes the biasing f moment.

2. The method of obtaining rapid acceleration for the opening andclosing of the contacts of a flasher for interrupting an electricalcircuit at frequent regular intervals, the ilasher having a contact armmounted for pivotal movement and the arm being continuously biasedtowards closed position by a moment which varies between a maximum atclosed position of the contacts and a minimum at fully open position,said method comprising: applying a counteracting moment to the arm whilethe contact arm is stationary, varying the counteracting moment toalternate it between values greater than the maximum and less than theminimum of the biasing moment, and restraining the contacts from anyrelative movement until the instant of separa-tion of the contacts.

3. The method of obtaining rapid acceleration for the opening andclosing of the contacts of a flasher of the type in which a pivotedcontact arm is continuously biased towards closed position and isperiodically held in open position by an opposing moment ofintermittently varying magnitude, said method comprising: arranging theopening land closing moments on the contact arm such that, upon bothopening and closing movement of the contact arm, the difference betweenthe moment causing the motion and the moment resisting the motion israpidly increased as the initial movement of the contact arm takes V4.The ,method of obtaning rapid acceleration forthe openingand closing ofthe contacts of a :.ilasher ofthe .type in which a pivoted contact arm:is continuouslyrbiased towards one positionrand is periodically heldinanother position by an opposing 'moment of intermittently varyingmagnitude, said method comprising: arranging the openingv andclosingmoments on-the contact arm such that, zupon` both opening and closingmovement of the contact arm, the difference between ,the moment causingthe motion and the moment iiresisting the motion is rapidly increased asmovement .of the Contact arm takes place, the contacts `being restrainedfrom any relativemove- `ment until the instantY of their separation.

v5. The method of Vobtaining rapid acceleration the arm beingcontinuously biased towards closed position by a single force causing amoment on the arm which varies between a maximum at closed position ofthe contacts and a minimum at fully open position, said methodcomprising: applying a single force causing a counteracting momentalternately varying between an amount greater than the maximum and lessthan the minimum of the first moment, the contacts being restrained fromany relative movement until the instant of their separation.

. 6. The method of obtaining rapid acceleration for the opening andclosing of the contacts of a flasher for interrupting an electricalcircuit at frequent regular intervals, the asher having a contact armmounted for pivotal movement between open and closed position and thearm being continuously biased towards one position by a moment varyingbetween a maximum at the one position and a minimum at the otherposition of the arm, said method comprising: applying a counteractingmoment to the arm and varying the counteracting moment to alternate itbetween an amount greater than the maximum and less than the minimum ofthe first moment, and storing the energy of the oounteracting momentwithout any relative movement of the contacts until such time as thecounteracting moment overcomes the biasing moment.

"1. A flasher of the hot-wire type, comprising: a switch arm pivotallymounted between its ends, one end portion being substantially rigid andthe other end portion being resilient, an electrical contact in the pathof movement of the switch arm, a spring biasing the switch arm atconstantly increasing moment as it approaches the contact, and atensioned wire intermittently heated by passage of electric current andhaving one end anchored and the other end attached to the resilient endportion of the switch arm for supplying a moment acting counter to themoment of the spring and alternately less than the minimum and greaterthan the maximum moment caused by the spring.

8. A flasher of the hot-wire type as claimed in claim '1, in which thewire is continually iny :an electric circuit through the flasher and thecurrent passing through the wire is varied by periodically establishinga circuit in shunt of the wire, whereby the wire is alternately heatedand permitted to cool.

9. A flasher, comprising: a switch arm pivotallyxmounted between. itsends, one endfportion being substantially yrigid andthe other end,portion `being resilient, `an electrical contact in the path ofmovement of the switch arm, a spring biasing the switch arm at.constantly increasing moment as it approaches the contact, andatensioned wire fandmeans to intermittently heat the same, the wirehaving one end anchored and the f otherl end attachedto the resilientend portionof the switch arm for. supplying a moment acting counter rtothe moment of the spring and alterf natelyless than the minimum andgreater than ythe maximum moment caused bythe spring.

l0. Ina asher for interrupting an electrical circuit at frequent regularintervals, a stack of superimposed plateshaving substantially continuoussimilar peripheries forming a housing, one of the plates being resilientand having an integral portion within the periphery ofthe plates forminga switch arm substantially coplanar with the plate and pivotallyattached to the peripherythereof for pivotal movement `in a plane.perpendicular tothe plate.

11. vIn a iiasher for interrupting an electrical circuit at frequentregular intervals, a stack of superimposed plates having substantially`continuous similar peripheries forming a housing, one of the pla-tesbeing resilient and having an integral portion within the periphery ofthe plate forming a switch arm substantially coplanar with the plate andpivotally attached to the periphery thereof for pivotal movement in aplane perpendicular to the plate, the pivoted mounting being formed by apair of overlapping offset kerfs in S ythe plate at each side of theswitch arm.

12. In a liasher for interrupting an electrical circuit at frequentregular intervals, a stack of superimposed pla-tes having substantiallycontinuous similar peripheries forming a housing, a switch arm mountedfor pivotal movement within the housing, and one of the plates beingresilient and having an integral portion within the periphery of theplate forming a switch-arm-biasing spring pivotally mounted on theperiphery for pivotal movement in a plane perpendicular to the plate,the pivotal mounting being formed by a pair of overlapping offset kerfsin the plate at each side of the spring.

13. In a flasher of the hot-wire type, a stack of superimposed plateshaving substantially continuous similar peripheries forming a housing,one of the plates forming a switch arm and a switch arm biasing springboth substantially coplanar with the plate and pivotally mounted on theperiphery thereof for pivotal movement in =a plane perpendicular to theplate.

14. A unitary organization constituting a flasher for periodicallyinterrupting a fiasher circuit combined with a relay responsive tocurrent ilowing through the flasher circuit for controlling a monitorcircuit showing operation of the flasher circuit, said flasher and relaycomprising a stack of superimposed plates having substantiallycontinuous similar peripheries formingY a housing, one of the platesincluding a pivotally-mounted switch arm biased to closed position tocomplete a low resistance asher circuit through the flasher, a hot-wirecontinuously in the flasher circuit for moving the switch arm tointerrupt the low resistance flasher circuit, and another of the platesincluding a relay switch arm biased to closed position to energize themonitor circuit, and a second hot-wire in series with the flashercircuit and responsive to drop in current through the flasher circuit toa predetermined minimum to move the relay switch arm against its biasand thereby interrupt the monitor circuit.

15. A combined flasher and relay as claimed in claim 14, in which theplate including the flasher switch arm and the plate including the relayswitch arm are similar.

16. A flasher comprising: a stationary contact and a movable contact; apair of spaced pivots; shiftable means extending operatively from onepivot to the other, the movable contact being carried by said shiftablemeans and said shiftable means being movable towards and away from saidstationary contact and continuously biased in one direction; resilientenergy-storing means located outside of the space between parallelplanes-passing through said pivots at right angles to a line connectingthe pivots, said energy-storing means being operatively connected tosaid shiftable means; and hot-wire control means connected to theenergy-storing means and operative to intermittently stress theenergy-storing means to store energy therein, the stored energy opposingthe bias of the shftable means, the

l2 stored energy periodically being of such magnitude as to overcome thebias of the shiftable means so as to actuate said shiftable means,thereby releasing a portion of the stored energy, the remaining storedenergy being additionally released over an interval of time by action ofthe control means decreasing the stress imposed upon the energy-storingmeans.

ROBERT S. PERRY.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,256,499 Schmidinger Sept. 23, 1941 2,291,895 Harmon Aug. 4,1942 2,354,635 Harmon July 25, 1944 2,367,614 Finlayson Jan. 9, 19452,368,679 Popp Feb. 6, 1945 2,388,712 Schmidinger Nov. 13, 19452,419,072 Hall Apr. 15, 1947 2,458,518 Kohl Jan. 11, 1949 2,525,044Puerner Oct. 10, 1950

